KVM: x86: hyper-v: Track Hyper-V TSC page status

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Create an infrastructure for tracking Hyper-V TSC page status, i.e. if it
was updated from guest/host side or if we've failed to set it up (because
e.g. guest wrote some garbage to HV_X64_MSR_REFERENCE_TSC) and there's no
need to retry.

Also, in a hypothetical situation when we are in 'always catchup' mode for
TSC we can now avoid contending 'hv->hv_lock' on every guest enter by
setting the state to HV_TSC_PAGE_BROKEN after compute_tsc_page_parameters()
returns false.

Check for HV_TSC_PAGE_SET state instead of '!hv->tsc_ref.tsc_sequence' in
get_time_ref_counter() to properly handle the situation when we failed to
write the updated TSC page values to the guest.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210316143736.964151-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

Vitaly Kuznetsov 2021-03-16 15:37:35 +01:00 • committed by Paolo Bonzini

parent e880c6ea55

commit cc9cfddb04

2 changed files with 52 additions and 14 deletions

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17

arch/x86/include/asm/kvm_host.h

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49

arch/x86/kvm/hyperv.c

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